Do I need to have vaccine if I have already suffered from COVID disease?

By एनयू ब्यूरो गुरुवार, 10 दिसंबर 2020 0 Edit

Prof Sundeep Mishra

It’s a challenging question right now since we don’t have the data we have to answer it and therefore no official guidance on it is available. We will have to go by logic till the data is available.

What do we know about COVID infection?

• Fact No 1. After COVID infection, Immunity developed isn’t life-long, and it can wane with time; quickly in some and bit more slowly in others. Administration of vaccine after COVID disease can confer additional immunity.

• Fact No 2: Even with most vaccines at least 2 doses are required. First vaccine dose generates a primary immune response against SARS -CoV -2 virus. However, the primary immune response is slow and weak as it takes days for the body to generate enough antibodies and T cells to eliminate the virus. However, the body generates long -lasting memory B and T cells that “remember” the SARS -CoV -2 virus, generating immune memory. Second vaccine dose generates a secondary immune response. The secondary immune response is stronger and quicker than the primary immune response as memory B and T cells are rapidly activated. This results in higher antibody concentrations and T cell counts around the body to eliminate the virus more quickly, reducing the symptoms and severity of COVID – 19 if there is infection. In addition, more memory B and T cells are produced after infection which strengthens memory of the SARS - CoV -2 virus. Thus prior COVID infection only helps boost immunity or ensures that complete immunity is developed by subsequent administration of vaccine.

• Fact No 3: Some virus for e.g. flu virus undergoing mutation and therefore require to redevelop immunity against the fresh strain. With COVID there is no data as yet, but this possibility has to be kept in mind.

• Fact No 4: There are well documented cases of re-infection; 40 patients or so reported from India itself. These patients might have been protected from re-infection if they had been vaccinated after the first infection.

What about side-effects of vaccine

Again, there is no solid data on this just yet, but looking at 2-dose vaccine protocol, there are reportedly no increase in side-effects after 2nd dose of vaccine as yet. Moreover, it is estimated that up to 10% of participants in the Pfizer and Moderna vaccine trials had had the virus (although they didn't directly recruit volunteers who were symptomatic or were known to have been previously infected) being either asymptomatic or with such mild symptoms that they went undetected. Fortunately the vaccines were found safe in these populations. Thus it seems that vaccination after COVID infection will also likely be safe.

Word of caution!

There is a word of caution for "long-haulers," COVID patients whose symptoms linger weeks and months after their diagnoses — they might be at certain risk if they receive vaccination.